Welding is a widely known process. Generally speaking, welding may be performed manually or, in some applications, it may be automated. Welding operations rely on a variety of types of equipment to ensure the supply of welding consumables (e.g., wire feed, shielding gas, etc.) is provided to the weld joint in an appropriate amount at the desired time. For example, a wire feeder is often used to provide welding wire at a desired feed rate to a welding torch.
Wire feeders facilitate the feeding of welding wire from a wire spool or drum to a welding torch at a desired wire feed rate. In general, prior art wire feeders incorporate at least one pair of rotating wire feed rollers to feed the wire. In these systems, the needed pulling friction between the rollers and the wire may be created by using one or both rollers to apply a squeezing pressure to the wire between the pair of rollers. In addition, some known wire feeders have grooves formed in one or both rollers to maintain the wire in position and/or to enhance or control the frictional forces between the wire and rollers.
Wire feeders of the type described above have a number of shortcomings. For example, long set up times are common as a user typically needs to open an access panel, and then open the feed mechanism to initially thread the wire through the wire feeder. In addition, the user often needs to change the rollers and wire guides when switching between welding wires of different diameters. In addition to the time it takes to switch the rollers/guides, this also introduces the possibility that the user may use the wrong set of rollers and/or guides. The user may also need to adjust the pressure of the feed rollers, which introduces the possibility that the user may incorrectly set the roller pressure, resulting in an undesirably high degree of wire deformation due to the high pressure. In addition, the mechanism may become clogged as a result of a peeled wire caused by too much pressure and/or nonalignment in the mechanism, and unreliable feeding of the wire due to wire slippage (contact point friction). Further, safety issues (e.g., finger pinching and the like) may be a concern as a user accesses and opens the mechanism. Furthermore, prior art wire feeders that rely on a pair of rotating rollers generally require a high level of maintenance, which results in high maintenance costs associated with buying and stocking spare parts, and which increases the potential for improper maintenance practices.
One solution that has been used to overcome some of these shortcomings, has been to incorporate a second pair of rotating rollers immediately after the first pair of rotating rollers. In use, movement of the first and second pair of rotating rollers is synchronized. By adding a second pair of rollers, the relatively high surface pressure on the wire may be halved. Unfortunately, adding a second pair of rollers often creates new issues. For example, with the introduction of a second pair of rollers, an increased risk exists for tangling of the wire, especially between the two pairs of rotating rollers. Also there is an increased risk of “shaving,” which is the tearing-away of material from the surface of the wire due to misalignment between the grooves formed in the rotating rollers and associated nozzles, and due to slipping of the wire relative to the rotating rollers. This can increase the possibility of clogging of the feed mechanism, the torch cable liner, and the torch.
In view of the foregoing, it would be desirable to provide a wire feeder device for welding that overcomes the shortcomings associated with prior art devices.